Key to the larvae of Megistopus

1 Spiracles pedunculated; mesothoracic spiracles longer than the mesothoracic setiferous processes; dolichasters covering the clypeo-labrum and labial palps black; IX abdominal sternite without markings (Fig. 18).................... M. flavicornis

- Spiracles not pedunculated; mesothoracic spiracles shorter than the mesothoracic setiferous processes; dolichasters covering the clypeo-labrum and labial palps whitish; IX abdominal sternite with markings (Fig. 19)...................... M. lucasi